Patients will be admitted to the CRC for one day on two separate occasions. Patients will be admitted NPO in he morning of the experiment. An IV will be started with saline from which periodic blood samples will be taken at later time points during the day. The patient will be giv en a physical examination by Dr. Adler before the protocol is started. The patient will lie quietly for 30 minutes after the IV is put in and physical exam is administered. The patient will then have her evoked potentials are then recorded. The patient will then have neurophyscology tests administered by the investigative team. The patient will then be given either nicotine gum or placebo to chew for 5 minutes and then spit out. If the patient is a non smoking normal control not on neuroleptic medication, they will be given 60 mg-90 mg of propanthaline prior to treatment with either placebo or nicotine gum. 10 minute, 60 minute and 120 minute periods, evoked potential recording, neuropsychology tests and blood will be repeated.